OggPlay is an audio player for smartphones. OggPlay was initially written for SonyEriccson P800 and then released under the GPL by Leif H. Wilden. In a true open source project, OggPlay has been since ported to several Symbian phones.
Main features of OggPlay:
Plays .ogg audio files
Detects and plays audio format supported the phone (MP3, AAC, MP4,M4A)
Skins (you can make your own, or use already made ones)